Blocking projects won't keep oil in the ground.

The United States has 72,000 miles of crude oil pipeline. Yet each proposal to add 1,000 miles or so is viewed by opponents in almost apocalyptic terms.

Activists spent years defeating the Keystone XL pipeline, which would have transported oil from western Canada and eastern Montana to the Gulf of Mexico.

Now the focus is on the Dakota Access Pipeline, a mostly built line running diagonally through the Dakotas and Iowa on its way to Illinois. It would be the first major pipeline bringing access to the Bakken oil fields that have been so much a part of America’s energy production renaissance.

On Sunday, the Army Corps of Engineers said it would not approve an easement to cross the Missouri River at the Standing Rock Sioux reservation, where protesters have been holed up for months. The decision by the Obama administration effectively punts the issue to the Trump administration, which would do well to explore whether there are less controversial ways to complete the pipeline.

For the Standing Rock Sioux, it is understandable that they would not want a pipeline crossing a major river just upstream of their reservation (and traversing land outside of the reservation said to contain sacred burial sites).

But their protests have been joined by environmental groups with larger aims. Some have couched their position in terms of respecting the rights of Native Americans, while others oppose the project outright. All see blocking the project as way to win a victory over Big Oil and to help wean the nation off fossil fuels.

Trying to fight climate change by fighting pipelines is a bit like fighting obesity by taking on selected sugar growers. If oil is in the ground and is profitable to extract, it will find its way to market, perhaps on rail cars that are more likely to spill, or perhaps on a different pipeline route.

That was the lesson from Keystone XL. Environmentalists killed the project on the grounds that the tar sands oil it would move was unusually polluting. But last week, the Canadian government approved an alternative route that will take the oil over the Rocky Mountains to Pacific Ocean ports. So much for keeping the oil in the ground.

The issue of where to route pipelines is always going to be a sticking point. Native tribes are not the only ones who would prefer to not have them in or near their backyards. But pipelines fill a vital need for the economy and for America’s energy security, and therefore need to be built.

As for combating climate change, the ultimate goal of many environmental groups, taking on individual pipelines is not the answer. The answer is to impose costs on carbon emissions so polluters can't keep using the atmosphere as a free dumping ground for greenhouse gases. That way, markets can figure out the best way to adapt.

Pipeline fights can make for a great spectacle. But, no matter which side wins, they will have little impact on the environment beyond their immediate environs.

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